Download Invasive Plant Guide - Alliance of Rouge Communities

Draft Version - Please note that this is a draft
version of this field guide.
Invasive Plant Species
of Michigan
Feedback - We would appreciate your feedback
regarding this booklet.
Comments and suggestions can be sent to Kim
Borland (email: [email protected]) or Suzan
Campbell (email: [email protected]).
A Pocket Guide
Compiled by:
Kim Borland, Suzan Campbell,
Becky Schillo & Phyllis Higman
11
Contents
Using this booklet ......................................................... 3
Herbarium specimens & early response ....................... 4
Trees
Black Alder ................................................................... 5
Black Locust ................................................................. 6
Russian Olive................................................................ 7
Norway Maple .............................................................. 8
Tree of Heaven.............................................................. 9
Autumn Olive ............................................................. 10
Shrubs
Black Jetbead .............................................................. 12
Amur Honeysuckle ..................................................... 13
Bell’s Honeysuckle ..................................................... 14
Morrow’s Honeysuckle ............................................... 15
Tartarian Honeysuckle ................................................ 16
Common Buckthorn ................................................... 17
Glossy buckthorn ........................................................ 18
Japanese Barberry ....................................................... 19
Multiflora Rose ........................................................... 20
Privet ........................................................................... 21
Woody Vines
Japanese Honeysuckle ................................................ 23
Kudzu ......................................................................... 24
Oriental Bittersweet .................................................... 25
Herbaceous Plants
Dame’s Rocket ............................................................ 27
Garlic Mustard ............................................................ 28
Giant Hogweed ........................................................... 29
Giant Knotweed .......................................................... 30
Japanese Knotweed..................................................... 31
Japanese Stilt Grass .................................................... 32
Leafy Spurge ............................................................... 33
Mile-a-minute Weed ................................................... 34
Narrow-leaved Bitter-cress ......................................... 35
Narrow-leaved Cat-tail ............................................... 36
Purple Loosestrife ....................................................... 37
Reed Canarygrass ....................................................... 38
Giant Reed .................................................................. 39
Spotted Knapweed ...................................................... 40
Swallow-worts ............................................................ 41
Canada Thistle ............................................................ 42
European Swamp Thistle ............................................ 43
Wild Parsnip ............................................................... 44
White Sweet Clover .................................................... 45
Yellow Sweet Clover .................................................. 46
Aquatic Plants
Curly Pondweed.......................................................... 48
Eurasian Water Milfoil ............................................... 49
European Frog-bit ....................................................... 50
Hydrilla ....................................................................... 51
Water-hyacinth ............................................................ 52
References .................................................................. 53
Photo Credits .............................................................. 56
Index ........................................................................... 59
2
Using this booklet
This booklet is intended to help you identify common invasive
species easily, so that control efforts can be initiated while
infestations are small. It includes a description of each plant, its
habitat preferences, reproductive strategies and a quick overview of
suggested control methods.
When invasive species are discovered early, hand pulling and
ongoing monitoring may be an effective means of control. In some
cases, all plant parts should be removed and destroyed, and this is
noted in the text.
This booklet does NOT provide detailed information on using
specific herbicides. Land managers are responsible for obtaining
any necessary licenses or permits, determining that particular
herbicides are registered in Michigan, and approved by their
agency. Herbicides must be used in accordance with label
instructions. Note potential damage to non-target plants and
precautions for safe use.
For large infestations, a detailed, integrated approach may be
required. Every site and infestation is unique and control efforts
should take specific details into account.
How old is a specific invasive population? Often, established
populations with extensive root systems may require higher
concentrations of herbicide. Are high quality populations of native
species present? In some cases, herbicides can be applied during
the dormant season. In other cases, herbicides that only target
broadleaved weeds, for example, might be most appropriate.
into the roots along with stored resources and can be particularly
effective. Similarly, for annual or biennial invasive species,
mowing while the plant is in bud can provide an effective means of
control.
In some cases, control efforts at the wrong time of year may
actually result in an increase in size or vigor of an invasive population.
In every case, success or failure of a particular control method
depends on a number of variables: the site, including slope, soil
texture and proximity to water; the particular species; the age and
extent of the infestation; the particular herbicide or mechanical
control under consideration; and the timing of control efforts.
Given the lack of available resources in addressing the spread of
invasive species, it is worth the time to thoroughly research a
particular species before initiating an extensive control effort.
Assess the entire region in determining priorities.
The following online resources provide a detailed
overview of the existing literature on the control and
eradication of a number of invasive species:
The Nature Conservancy’s Global Invasive Species Initiative
Invasives and Control Methods -Provides abstracts that summarize
plant descriptions, biology and current research for controlling
specific invasive species:
http://tncweeds.ucdavis.edu/esadocs.html
Some species may be effectively controlled by prescribed fire or
mowing, while in other cases, these methods are ineffective when
used alone, but may be effective in conjunction with herbicides.
U.S.D.A. Forest Services Fire Effects Information System
(FEIS)
Provides invasive species summaries with detailed information on
plant biology, ecology, fire behavior and control methods:
http://www.fs.fed.us/database/feis/plants/weed/weedpage.html
Control timing is also a critical factor in determining the success of
a particular method. While many herbicides are best absorbed by
young leaf tissue, the herbicide may not be effectively drawn down
into plant roots while plants are actively growing.
USDA National Agricultural Library
National Invasive Species Information Center - Provides links to
current federal, state and academic literature on selected invasive
species: http://www.invasivespeciesinfo.gov/plants/main.shtml
When herbicide is applied as the plants die back, it is often drawn
3
Herbarium specimens & early response
Invasive species present an emormous threat to Michigan’s native
biodiversity. Tracking the spread of new invasives before they are
well-established is a critical first step in fighting this onslaught. At
the time of this writing, Michigan has no centralized database
dedicated to documenting the spread of invasive species within the
state.
The University of Michigan’s Herbarium’s Online Atlas, at:
http://herbarium.lsa.umich.edu/website/michflora/
provides the most comprehensive record of the distribution of
invasive plant species at present, although there is a substantial
time lag before new specimens are posted.
Trees
You can help track the spread of invasive species by submitting
specimens for species that have not yet been recorded in a
particular county.
Specimens should be pressed and dried in a plant press before
submission. If a plant press is unavailable, specimens may be dried
between several newspaper sheets, layered between pieces of
corrugated cardboard and tightly bound.
Detailed instructions for preparing specimens are available at the
the University of Florida’s Herbarium website at:
http://www.flmnh.ufl.edu/herbarium/voucher.htm
Specimens should be submitted unmounted, with a label that
includes:
• Scientific Name
• Collector (and other individuals who were present)
• Locality (including GPS coordinates, if possible)
• Habitat, site quality, species abundance and extent
• Collection Number (assigned by collector)
• Date of Collection
Ship to:
Anton Reznicek, Curator (Vascular Plants),
University of Michigan Herbarium
3600 Varsity Drive,
Ann Arbor, MI 48108-2287.
4
Black Alder
Alnus glutinosa
60
60
60
27
60
32
32
Habit: Deciduous, medium tree, ranging from 9-15 m (30-50 ft) in
height and 2.5-5 cm (1-2 in) in diameter; narrow pyramidal shape
when young, becoming more irregular with age.
Leaves: Simple, alternate, broadly rounded to truncate or notched
at the apex; 5-13 cm long and 5-10 cm wide; toothed leaf margin;
young leaves sticky to the touch; fall leaves green or brown.
Stems/Bark: Dark green-brown, smooth or rough; speckled with
short lenticels; bark with prominent warty strips; buds stalked.
Flowers: Male and female flowers in separate structures; male
flowers borne on long narrow catkins; female flowers borne in
small woody structures resembling pinecones; bloom March-May.
Fruits/Seeds: Small, glutinous, woody, pinecone-like structure
borne on long, narrow stalks; seeds are small and narrowly
winged.
Habitat: Prefers full sun and wet soil but tolerant of drier soil and
a range of pH conditions; found along rivers, in wetlands and
moist forests.
Reproduction: By seed and spreading roots.
Similar Species: Native - Speckled alder (Alnus rugosa) - leaves
with a distinct (acute) tip, usually shrubbier than A. glutinosa.
Comments: Capable of displacing desirable vegetation; fixes
nitrogen; has been planted on highly disturbed or infertile sites and
for windbreaks; several cultivars including pyramidal forms and
trees with finely dissected leaves; vulnerable to tent caterpillar.
Monitoring & Rapid Response: Monitor pond, river and wetland
margins; distinguishable year-round by its rounded leaves, catkins,
cones and stalked vegetative buds; begin control efforts in highest
quality areas and remove mature trees that provide a source of
seed; hand pull seedlings, young shrubs; resprouting likely
following cutting, girdling, mowing, burning etc.; treat cut stumps
with herbicide; all stems must be treated.
5
Black Locust
Robinia pseudo-acacia
35
61
13
18
3
60
Habit: Deciduous medium tree ranging in height from 12-25 m
(40-82 ft) and 30-60 cm (12-24 in) in diameter; crown narrow,
open, irregular with contorted branches.
Leaves: Pinnately compound with 7-21 leaflets per leaf; alternate,
20-35 cm long; ovate leaflets 2-5 cm long and about half as wide,
with smooth margins; hairless, very thin; dull bluish green above
paler beneath, turning yellowish brown in the fall.
Stems/Bark: Twigs puberulent, becoming smooth, green to
reddish brown, with zigzag shape and two spines at each node;
bark is thick, tan to gray-brown, deeply furrowed; inner bark
orange.
Flowers: White, 5-petaled, pea-like, very fragrant; raceme of 1025 on a thin dangling pedicel; bloom May-June.
Fruits/Seeds: Seedpods form in the fall but persist over winter,
pods are smooth, dark-brown, flat, and contain 4-8 small, flat,
brown seeds.
Habitat: Very shade intolerant; can grow in many soil types
except those with a high water table; formerly widely planted in
Michigan and now found colonizing old fields, prairies, disturbed
forests and woodlands.
Reproduction: By seed; also sprouts easily from roots and forms
natural clones.
Similar Species: Honey locust (Gleditsia triacanthos) has smaller,
more numerous leaflets.
Comments: The nitrogen fixing capacity of this species may alter
soil chemistry and subsequent nutrient cycling of forest systems.
Monitoring & Rapid Response: Monitor prairie and woodland
edges and paths, particularly on well-drained soils; most visible in
May and June while in flower; cutting, girdling and burning are
ineffective without herbicide as they stimulate sprouting; mowing
stimulates germination of the (black locust) seedbank; treat cut
stumps with herbicide; foliar application of bud inhibitor effective
on trees under five feet tall; basal bark treatment also effective,
may be used in conjunction with girdling.
6
Russian Olive
Elaeagnus angustifolia
61
35
8
35
42
40
Habit: Deciduous thorny shrub or small tree growing up to 9
meters (30 feet) in height, rounded in shape with a loose
arrangement of branches.
Leaves: Simple, alternate, oblong, 4-8 cm long, untoothed
margins; light green and covered with silvery star-shaped hairs
above, silvery white and densely covered with scales below.
Stems/Bark: Slightly thorny on ends; silvery scales present when
young; bark is thin and comes off in elongated strips.
Flowers: Small, highly aromatic yellowish flowers, silver inside;
umbel-shaped, single or clustered; usually flowers early (JuneJuly), shortly after leaf emergence.
Fruits/Seeds: Hard, yellow-red, olive-shaped fruits, 0.5 inches
long with silvery scales, clustered along stems in great quantities;
eaten and dispersed by many bird species; begin fruiting at 3 to 5
years.
Habitat: Relatively shade tolerant; invades open and disturbed
areas; can occur in a variety of soil and moisture conditions; not
tolerant of acidic conditions (pH<6.0).
Reproduction: Primarily by seed, also vegetatively or by root
sucker at the root crown.
Similar Species: non-native autumn olive (Elaeagnus umbellata)
has shorter, broader, slightly less silvery leaves; closely related
native Shepardia spp. have opposite leaves, usually smaller.
Comments: Forms a dense, monospecific shrub layer displacing
native species and closing open areas; alters nutrient cycling and
hydrology of a system; 4th most common riparian tree in the West.
Monitoring & Rapid Response: Monitor edge habitats,
particularly along streams and rivers; early detection is critical as
large stands are almost impossible to eradicate; hand pull
seedlings while soil is moist; small seedlings susceptible to fire;
burning, mowing, cutting and girdling all stimulate resprouting in
larger plants unless accompanied by herbicide treatment; treat cut
stumps with an herbicide; basal bark/stem sprays effective on
younger trees; foliar herbicide sprays effective for small trees,
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resprouts.
Norway Maple
Acer platanoides
Habit: Medium tree reaching 12-18 m (40-60 ft) in height and 3060 cm (12-24 in) in diameter; crown is dense, symmetrical, and
rounded; spread is approximately two-thirds of the tree’s height.
Leaves: Simple, opposite, green to bronze, smooth, 5-7 lobed with
few teeth and broad bases up to 18 cm wide; wider than long;
petioles with a milky juice; leaves retained late in autumn.
Stems/Bark: Stout twigs, smooth, olive brown; leaf scars meet to
form a sharp angle; buds are plump, rounded, fleshy, green to
maroon; one large bud in center with two smaller lateral buds;
bark is grayish black with small furrows.
Flowers: Stalked, yellow-green and perfect; in loose clusters;
appearing before or with the leaves in spring.
Fruits/Seeds: Two-winged samaras with the wings almost
horizontally (180 angle) divergent; seeds are wind dispersed with
low fall rates; appear in late spring through summer.
Habitat: Shade tolerant; occurs in a variety of soil and moisture
conditions but prefers fertile, moist, well-drained soils; found on
roadsides, waste places, hedgerows, roadside thickets and
disturbed forest communities; somewhat resistant to drought.
Reproduction: By seed.
Similar Species: Native - Sugar maple (A. saccharum) - does not
produce milky juice; samara wings are at an angle and leaf scars
do not meet.
Comments: At least 36 cultivars; creates dense shade;
monopolizes soil moisture; regenerates prolifically under its own
canopy, can reduce overall plant diversity of a site.
Monitoring & Rapid Response: Monitor forest edges and paths;
stays green until November, can be identified in spring, summer
and early fall by the milky sap in its leaves and stems; for large
infestations, focus on highest quality areas and remove mature
trees that provide a source of seed; hand pull seedlings in spring
while soil is moist; girdle mature trees - spring most effective;
treat cut stumps with herbicide, may enhance effects of girdling;
basal bark treatment effective for trees less than 4” in diameter.
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Tree of Heaven
Ailanthus altissima
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2
42
54
35
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Habit: Deciduous small to large tree; 12-20 m (40-65 ft) tall and
60-100 cm (24-40 in) in diameter; crown wide-spread with
multiple branches.
Leaves: Pinnately compound with 11-30 lance-shaped leaflets per
leaf; alternate; large - 30-90 cm long; entire, except for 1-5 small
gland tipped teeth near the base; dark green above, pale green
below, turn yellow in fall; unpleasant odor resembling rancid
peanut butter when crushed.
Stems/Bark: Twigs very stout, light to dark brown, smooth with
large V-shaped leaf scars; bark thin, gray to brownish gray, smooth
with shallow fissures appearing on older trunks
Flowers: Small; yellow-green; 5-petaled; borne in dense clusters
near ends of upper branches; bloom in late spring; male and
female flowers on different plants; pollen has an offensive odor.
Fruits/Seeds: Two-winged papery, flat, samara with a single seed
in the middle; develop in clusters on female trees in fall; may
remain on tree through winter; germinate readily; dispersed by
wind, birds and water.
Habitat: Shade intolerant; thrives in poor soils; found in disturbed
soils, fence rows, fields, roadsides, woodland edges, forest
openings and rocky areas; very fast growing.
Reproduction: By seed and vegetatively via root suckering, up to
350,000 seeds produced annually by a single plant.
Similar Species: Native - sumacs (Rhus glabra, R. typhina);
walnuts (Juglans nigra, J. cinerea) - crushed leaves or broken
stems of these plants lack rancid peanut butter aroma.
Comments: Extensive cloning; allelopathic properties present.
Monitoring & Rapid Response: Monitor edges, paths; hand pull
seedlings before taproot develops (< 3 months) as taproot
fragments may resprout; resprouts following cutting, girdling,
mowing, burning - follow-up treatment required; girdling followed
by herbicide most effective; treat cut stumps with an herbicide most effective in late spring & all stems in a clone must be treated;
basal bark/stem sprays with herbicide provide good root kill,
particularly in fall; foliar herbicide spray is effective on small
9
trees.
Autumn Olive
Elaeagnus umbellata
Habit: Deciduous shrub or small tree growing up to 6 meters (20
feet) in height and 9 meters (30 feet) wide.
Leaves: Simple, alternate, oval, 5-10 cm (2-4 in) inches long;
entire margins, wavy; gray-green above, silvery scaly below; early
leaf out (mid-March).
Stems/Bark: Often thorny; silvery or golden brown, with
brownish scales giving stems a speckled appearance.
Flowers: Fragrant; tubular; 4 petals and stamens; cream to light
yellow; in clusters of 1-8; flowers from April to June.
Fruits/Seeds: Occur in drupes; 0.25 inches; silvery with brown
scales when immature, speckled red or yellow when mature; ripen
September to October; begin to bear fruit at 3 to 5 years; each tree
can produce 2-8 lbs. of seed per year.
Habitat: Shade tolerant; occurs in a variety of soil types (pH
range of 4.8-6.5), thrives on infertile soils because of nitrogenfixing root nodules; found in open woods, forest edges, roadsides,
fencerows, meadows, sand dunes, and other disturbed areas.
Reproduction: Primarily by seed, also by stump sprouting and
roots.
Similar Species: Native - Silver-berry (E. commutata) has
opposite leaves; non-native Russian olive (E. angustifolia) has
longer, narrower, leaves, silver above.
Comments: Invades disturbed areas, resprouts quickly; can outcompete native species; increases nitrogen levels to the detriment
of native communities.
Monitoring & Rapid Response: Monitor sunny open sites;
autumn olive leafs out early in spring, retains leaves in fall, can be
recognized year-round; hand pull seedlings; focus on highest
quality areas first; burning and cutting stimulate resprouting; treat
cut stumps with an herbicide, best in fall; basal bark/stem sprays
effective in late spring, possibly in fall; foliar herbicide sprays
effective for small trees and resprouts but may harm non-target
plants; basal stem injection of herbicide on dormant plants
provides excellent control with low concentrations of herbicide.
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Shrubs
11
Black Jetbead
Rhodotypos scandens
10
42
10
10
Habit: Open, arching shrub ranging in height from 1-2 m (3-6 ft)
in height and 1.2-2.7 m (4-9 ft) in width.
Leaves: Simple, opposite, bright green, 5-10 cm (2.25-4) in long;
doubly toothed margins, rough texture on the leaf surface; resemble
raspberry leaflets; emerge early in spring, retained until late fall.
Stems/Bark: Stems arching, loosely branched.
Flowers: White, 4-petaled, occurring singly at branch tips, bloom
in late April, early May, occasional flowers later in season.
Fruits/Seeds: Fruits are black, hard and ovoid, 1cm (0.3 in) long;
clustered at branch tips, hanging below leaves; persist over winter.
Habitat: Native to China and Japan; escaped ornamental capable
of invading forests; prefers sunny, dry, well-drained sites but
thrives in shade and in harsh urban conditions.
Reproduction: by seed; possibly bird-dispersed.
Similar Species: slightly resembles other opposite leaved shrubs
including honeysuckle and privet but form more open and arching,
fruits clustered at stem tips, rather than along branches.
Comments: Although jetbead is a member of Rosaceae, its leaves
are opposite, rather than alternate.
Monitoring & Rapid Response: Monitor woodland edges and
along paths; jetbead is most visible while its white flowers with
four petals are in bloom in spring; pull seedlings and hand dig
small plants; for large infestations, cut shrubs to the ground in fall
or winter; may be controlled with herbicide, applied in spring;
little information is available on this species but applying
herbicide to cut stems is likely to enhance control efforts.
As this species has a limited distribution in Michigan, it is
important to document new occurrences.
10
Please obtain flowering or fruiting specimens and
submit to: Anton Reznicek, Curator (Vascular Plants),
University of Michigan Herbarium, 3600 Varsity Drive,
Ann Arbor, MI 48108-2287.
12
Amur Honeysuckle
Lonicera maackii
2
35
35
3
2
42
20
59
Habit: Deciduous upright to spreading shrub growing up to 5 m
(16-18 ft) tall.
Leaves: Simple, opposite, slightly hairy, elliptical leaves; 4-9 cm
long; smooth margins and a long distinctive apex or “drip tip”;
early leaf out; long growing season.
Stems/Bark: Multiple stems, numerous arching branches; thick
non-exfoliating gray to tan bark with noticeable interlacing ridges;
older branches often hollow.
Flowers: Small, white to pink, tubular, paired flowers on short
(0.5 cm) stalks arising from the leaf axils; blooms May-June;
fragrant.
Fruits/Seeds: Berries are red and paired, borne on very short
stalks; abundant; persistent; dispersed by birds.
Habitat: Relatively shade intolerant; occurs in a variety of soil
and moisture conditions; invades open forests, savannas and
prairies; disturbed areas are particularly vulnerable to invasion.
Reproduction: By seed; dispersed by birds.
Similar Species: Canada honeysuckle (L. canadensis), American
fly honeysuckle (L. involucrata), fly honeysuckle (L. oblongifolia)
and swamp fly honeysuckle (L. villosa). Native honeysuckles are
relatively short, sparse shrubs as compared to non-native species.
Comments: Usually distributed near large urban areas but also
occurs in rural areas where it was planted for wildlife food and
cover; forms dense thickets; inhibits growth of native plant
species, reducing tree and shrub regeneration and decreasing
overall plant diversity; birds nesting in this shrub experience
increased nest predation in comparison with native shrubs.
Monitoring & Rapid Response: Monitor sunny, upland sites and
open forests in spring as honeysuckle leafs out before natives;
begin control efforts in highest quality areas; target large, fruitbearing plants; hand pull or dig seedlings or small plants in spring;
foliar spraying may be effective for large populations where few
natives are present; treat cut stumps with herbicide in fall/winter;
basal bark treatment is also effective - spray bottom 18 inches of
all stems; prescribed fire provides effective control.
13
Bell’s Honeysuckle
Lonicera xbella
33
20
33
33
59
Habit: Deciduous upright to spreading shrub growing up to 5.5 m
(18 ft) tall; hybrid between Tartarian and Morrow’s honeysuckles;
shallow roots.
Leaves: Simple, opposite, elliptic to oval or oblong; slightly hairy
beneath; 3-6 cm long; early leaf out, long growing season.
Stems/Bark: Multiple stems, arching branches; older branches
hollow between nodes; pith brown; bark is gray or tan, shaggy.
Flowers: Small, pink, tubular, paired and fragrant; borne on stalks
(0.5-1.5 cm long) arising from the leaf axils; blooms May to June
Fruits/Seeds: Berries are red and paired; dispersed by birds.
Habitat: Sun and shade tolerant; occurs in a variety of soil and
moisture conditions; found along roadsides and on disturbed sites;
invades forest, savannas and prairies.
Reproduction: By seed, dispersed by birds.
Similar Species: American fly honeysuckle (L. canadensis),
bracted honeysuckle (L. involucrata), swamp fly honeysuckle (L.
oblongifolia) and mountain honeysuckle (L. villosa). Native
honeysuckles are relatively short, sparse shrubs as compared to
non-native species.
Comments: Especially affects woodlands and disturbed habitats;
usually distributed near large urban areas, but also occurs in rural
areas where it was planted for wildlife food and cover; can form
dense thickets in a forest under-story, shading out herbaceous
plants, reducing tree and shrub regeneration, and decreasing
overall plant diversity.
Monitoring & Rapid Response: Monitor sunny, upland sites and
open forests in spring as honeysuckle leafs out well before native
species; begin control efforts in highest quality areas; target large,
fruit-bearing plants; hand pull or dig seedlings or small plants in
spring; foliar spraying may be effective for large populations
where few natives are present; treat cut stumps with herbicide;
basal bark treatment is also effective - spray bottom 18 inches of
all stems; prescribed fire provides effective control.
14
Morrow’s Honeysuckle
Lonicera morrowii
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33
20
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42
Habit: Deciduous upright to spreading shrub growing up to 1.8 m
(6 ft) tall.; shallow roots.
Leaves: Simple, opposite, elliptical to oblong; short; gray-green,
softly hairy beneath; 3-6 cm long; early leaf out, long growing
season.
Stems/Bark: Multiple stems; numerous arching branches; older
branches often hollow; bark is gray or tan, shaggy.
Flowers: Small, white, tubular, paired, hairy and fragrant; borne
on hairy stalks (0.5-1.5 cm long) arising from the leaf axils;
blooms May-June.
Fruits/Seeds: Berries are red and paired; dispersed by birds.
Habitat: Sun and shade tolerant; occurs in a variety of soil and
moisture conditions; commonly found along roadsides and on
disturbed sites; invades forest, savannas, and prairies.
Reproduction: By seed; dispersed by birds.
Similar Species: Canada honeysuckle (L. canadensis), American
fly honeysuckle (L. involucrata), fly honeysuckle (L. oblongifolia)
and swamp fly honeysuckle (L. villosa). Native honeysuckles are
relatively short, sparse shrubs as compared to non-native species.
Comments: Especially affects woodlands and disturbed habitats;
usually distributed near large urban areas, but also occurs in rural
areas where it was planted for wildlife food and cover; can form
dense thickets in a forest under-story, shading out herbaceous
plants, reducing tree and shrub regeneration, and decreasing
overall plant diversity.
Monitoring & Rapid Response: Monitor sunny, upland sites and
open forests in spring as honeysuckle leafs out well before native
species; begin control efforts in highest quality areas; target large,
fruit-bearing plants; hand pull or dig seedlings or small plants in
spring; foliar spraying may be effective for large populations
where few natives are present; treat cut stumps with herbicide;
basal bark treatment is also effective - spray bottom 18 inches of
all stems.
15
Tartarian Honeysuckle
Lonicera tatarica
8
42
18
20
18
Habit: Deciduous upright to spreading shrub growing to 3 m (9 ft)
tall; shallow roots.
Leaves: Simple, opposite, oval to oblong, short, hairless, leaves
with pointed tips; 3-6 cm long and 2-4 cm wide with smooth
margins; dark green above and paler beneath; early leaf out, long
growing season.
Stems/Bark: Twigs are slender, brown to reddish with brown pith;
multiple stems; numerous arching branches; older branches often
hollow; bark is light gray, somewhat exfoliating.
Flowers: Small, pink to white, tubular, fragrant, paired flowers on
long (1.5-2.5 cm) stalks arising from the leaf axils; bloom MayJune.
Fruits/Seeds: Abundant, red or orange paired berries.
Habitat: Sun and shade tolerant; occurs in a variety of soil and
moisture conditions; commonly found along roadsides and on
disturbed sites; invades forest, savannas and prairies.
Reproduction: By seeds; dispersed by birds.
Similar Species: Canada honeysuckle (L. canadensis), American
fly honeysuckle (L. involucrata), fly honeysuckle (L. oblongifolia)
and swamp fly honeysuckle (L. villosa). Native honeysuckles are
relatively short, sparse shrubs as compared to non-native species.
Comments: Invades woodlands and disturbed habitats; found near
large urban areas and in rural areas where it was planted for
wildlife food and cover; forms dense thickets in a forest understory, shading out herbaceous plants, reducing tree and shrub
regeneration and decreasing overall plant diversity.
Monitoring & Rapid Response: Monitor sunny, upland sites and
open forests in spring as honeysuckle leafs out well before native
species; begin control efforts in highest quality areas; target large,
fruit-bearing plants; hand pull or dig seedlings or small plants in
spring; foliar spraying may be effective for large populations
where few natives are present; treat cut stumps with herbicide;
basal bark treatment is also effective - spray bottom 18 inches of
all stems.
16
Common Buckthorn
Rhamnus cathartica
14
42
59
59
42
42
18
Habit: Deciduous, woody shrub to small tree ranging from 3-7.5
m (10-25 ft) in height and reaching 25 cm (10 in) in diameter.
Leaves: Simple, opposite to sub-opposite, oval, dark green,
smooth and shiny; small teeth along margins; veins that curve from
base towards leaf tip; early leaf out, long growing season.
Stems/Bark: One to several stems from the base; stems branch
towards the crown; twigs with thorns often found near the tips;
bark is brown to gray, peeling with age, dotted with vertical lightcolored lenticels; inner bark is orange.
Flowers: Small, green-yellow, 4-petaled, clustered in leaf axils;
blooms May-June; fragrant.
Fruits/Seeds: Round, pea-size, black berries (on female plants
only); persistent through the winter.
Habitat: Widely planted as an ornamental shrub in hedge rows;
now found along roadsides, woodland edges, prairies, and old
fields.
Reproduction: By prolific fruit and seed production, seeds widely
dispersed by birds.
Similar Species: Alder-leaved buckthorn (Rhamnus alnifolia)less than 1 m (3 ft) in height with hairless twigs and dark scales on
winter buds; non-native glossy buckthorn (Rhamnus frangula) has
shiny leaves, always lacks terminal “thorn”(see page 15).
Comments: Produces a dense shade that can limit light to tree and
shrub seedlings, and native herbaceous groundcover, limiting
overall plant diversity; changes nutrient cycling by increasing
nitrogen and carbon.
Monitoring & Rapid Response: Monitor woodland edges and
paths on dry, well-drained soils; buckthorn leafs out early and
retains its leaves late into fall; begin control efforts in highest
quality areas; target large, fruit-bearing plants; hand pull or dig
seedlings or small plants in spring; foliar spraying may be
effective for large populations where there are few natives present;
treat cut stumps with herbicide as stumps sprout; basal bark
treatment also effective; monitor site and control new seedlings
until the seedbank is exhausted.
17
Glossy buckthorn
Rhamnus frangula (Frangula alnus)
42
32
14
42
32
Habit: Deciduous shrub or small tree growing up to 6 m (20 ft.)
tall, multiple stems at the base, crown spreading, trunk up to 10
inches in diameter.
Leaves: Simple, alternate, oblong, 1-2.5” long, untoothed or
crenulate margins, dark green, shiny; smooth or slightly hairy
below; veins turn toward tip near leaf margins; leaves present from
mid-May to November.
Stems/Bark: Brown-green, hairy, prominent lenticels, chunky
bark; terminal buds rust colored; bark gray or brown; sapwood
yellow; heartwood pinkish to orange.
Flowers: Small, greenish yellow, four petals, clusters of 2-6;
bisexual; blooms late May through September.
Fruits/Seeds: Round, pea-sized, drupes of 3-4 seeds, red, ripening
to black/dark purple in July through September; abundant; remain
viable in the soil for 2 to 3 years.
Habitat: Sun and shade tolerant; occurs in a variety of soil and
moisture conditions; found in pastures, fencerows, roadsides,
wetlands, and woodland edges.
Reproduction: Primarily sexual; plants mature quickly; at any
given time there can be flowers, partially ripened fruit (red) and
fully ripened fruit (black) on the same plant.
Similar Species: Alder buckthorn (R. alnifolia) - less than 3’ tall,
hairless twigs; Lance-leafed buckthorn (R. lanceolata) - less than
6’ tall, leaves 2-6” long, tapering.
Comments: Rapidly form dense, even-aged thickets, crown
spreads laterally; resprouts vigorously.
Monitoring & Rapid Response: Monitor woodland edges and
paths on moist soils; buckthorn leafs out early and retains its
leaves late into fall; begin control efforts in highest quality areas;
target large, fruit-bearing plants; hand pull or dig seedlings or
small plants in spring; foliar spraying may be effective for large
populations, where few natives are present; treat cut stumps with
herbicide; basal bark treatment is also effective; monitor site and
control new seedlings until the seedbank is exhausted.
18
Japanese Barberry
Berberis thunbergii
23
23
17
23
25
34
34
Habit: Spiny, deciduous shrub, typically 0.6-0.9 m (2-3 ft) tall.
Leaves: Simple, alternate, oval to spoon shaped with smooth
margins, 1.3-2 cm long; bright green above, lighter below, in
clusters at each node, red to purple in the fall depending on the
cultivar.
Stems/Bark: Numerous, spiny, slightly curving; older stems gray;
twigs and young stems turning reddish brown in winter; inner bark
yellow.
Flowers: Small, yellow, 6-petaled, stalked; single or in small
clusters of 2-4 blossoms; blooms April - May
Fruits/Seeds: Small, bright red, egg-shaped berries found singly
or in clusters on slender stalks; mature in midsummer; remain on
stems into winter; often dispersed by birds, deer, turkey and
grouse.
Habitat: Found along woodland edges, open woods, roadsides,
stream banks, old fields; tolerates a range of soil, moisture and
light conditions.
Reproduction: By seed, creeping roots and cut stumps; branches
root freely where they touch the ground.
Similar Species: American barberry (B. canadensis) - has toothed
leaves and usually 3-pronged spines.
Comments: Species is often planted as a hedge and escapes from
cultivation; at least 47 cultivars exist; growth minimal in low light;
deer herbivory minimal.
Monitoring & Rapid Response: Monitor sunny open sites and
edges in spring when barberry leafs out before native shrubs;
remove all plants before seed is produced; begin control efforts in
highest quality areas and remove mature shrubs that provide a
source of seed; hand pull or dig young plants, removing all roots;
treat cut stumps with herbicide; foliar herbicide spray is effective
on areas with few native plants; cut shrubs at base in winter so that
only resprouts need to be sprayed in spring.
19
Multiflora Rose
Rosa multiflora
Habit: Deciduous, dense, perennial shrub growing up to 5 m (16
ft) tall and 2.7-3.9 m (9-23 ft) wide, with long, slender, arching
branches.
Leaves: Alternate, pinnately compound with 5-11 leaflets; leaflets
2.5 cm long and finely toothed; base of leaf with a fringed
appendage (stipule).
Stems: Green-reddish, arching, rigid with re-curved thorns.
Flowers: Numerous, white or slightly pink, 5-petaled, 1-4 cm
wide; arranged in a panicle; bloom May-June.
Fruits/Seeds: Fruits are small, clustered, hard, smooth, red, rose
hips that appear in September-October and last into winter; seeds
yellowish and dispersed by birds and mammals, remain viable for
10-20 years.
Habitat: Found along roadsides, pastures, disturbed areas, forests
and streambanks; tolerates a variety of soil conditions; prefers
open, well-drained sites.
Reproduction: By seed; also by horizontal stems that root at the
node and shoots that root at the tips.
Similar Native Species: Several native species of Rosa; native
roses usually have pink flowers and do not have fringed stipules.
Comments: Introduced from Japan and Korea in the 1800s; later
promoted to control soil erosion, as a living fence and for wildlife
food and cover; vulnerable to Japanese beetles and a number of
other pests and diseases.
Monitoring & Rapid Response: Monitor paths, edges and open
areas; dig out small plants after tops have been cut and removed;
remove all roots; cutting or mowing several times throughout the
growing season for several years may reduce populations; treat cut
stems with herbicide; basal bark treatment effective - spray bottom
18 inches of all stems; foliar application of bud inhibitor (effective
only on woody species) causes dieback the following year; foliar
herbicide application effective but may injure non-target species.
18
35
4
59
35
3
20
Privet
Ligustrum vulgare
3
3
3
3
3
3
3
Habit: Bushy, stout, shrub with unevenly spreading branches,
ranging in height from 3.5-4.5 m (12-15 ft), with a comparable
spread.
Leaves: Simple, opposite, elliptic to ovate, 3-7 cm long, smooth
margins, dark green above and paler beneath, turning purplish in
fall; leafs out early, retains its leaves into the late fall/early winter.
Stems/Bark: Young branches green, minutely puberulent,
becoming smooth with age; thin, gray-brown bark with lenticels.
Flowers: Small, white, 2.5-7.5 cm long, borne in terminal,
branched cluster; strong odor; bloom mid- June.
Fruits/Seeds: Fruits are small, lustrous, black, berry-like drupes
that ripen in September and persist on the shrub through winter.
Habitat: Ornamental shrub that has escaped to colonize disturbed
areas, forests, and grasslands; can tolerate full sun to partial shade.
Reproduction: By seed; widely disseminated by birds.
Similar Species: superficially resembles honeysuckle species but
leaves are smaller, flowers/fruit held at branch tip, not along its
length.
Comments: Native to Europe, North Africa; planted widely
historically but now less utilized; vulnerable to anthracnose twig
blight.
Monitoring & Rapid Response: Monitor sunny, disturbed,
upland grasslands and forest edges; privet leafs out early in spring
and retains its leaves late in fall; hand pull or dig seedlings &
small plants; remove all roots to prevent resprouting; treat cut
stumps with herbicide; basal bark treatment is effective; foliar
spraying may be effective for large populations, where there are
few natives present; site should be monitored and new seedlings
controlled until the seedbank is exhausted.
21
Woody Vines
22
Japanese Honeysuckle
Lonicera japonica
2
1
3
19
2
2
3
Habit: Perennial, woody vine that can climb up to 7 m (23 ft) tall
and form a thick covering over trees, shrubs and groundcover
species.
Leaves: Simple, opposite, oval to lobed with smooth margins, 4-8
cm long; leaf base round/triangular; leaves are semi-evergreen to
evergreen.
Stems/Bark: Hairy, reddish/light brown, woody, hollow.
Flowers: White-cream-pink, paired, tubular flowers arising from
leafs axils along stems; bloom April-June; fragrant.
Fruits/Seeds: Black to purple, glossy, paired fruit with 4-10
brown-black seeds.
Habitat: Native to East Asia; found in open woods, old fields,
disturbed areas, roadsides and fence rows; moderately shade
tolerant but prefers full sun.
Reproduction: By seed and vegetatively by root suckers and
runners; sexual reproduction may be limited by lack of pollinators.
Similar Species: Native - Red honeysuckle (L. dioica), yellow
honeysuckle (L. flava), hairy honeysuckle (L. hirsuta), and grape
honeysuckle (L. reticulata) - native honeysuckle vines have redorange fruit and terminal, opposite leaves that unite at their bases
(connate).
Comments: Can be detrimental to native host due to root
competition for resources.
Monitoring & Rapid Response:
Monitor open areas and woodland edges; Japanese honeysuckle
retains some leaves over winter; cutting, pulling and burning
Japanese honeysuckle may weaken it but will not eliminate it;
foliar application of herbicide is effective; late autumn or winter
prescribed burns provide effective control when followed by foliar
herbicide application about a month after resprouts emerge;
minimize soil disturbance to prevent germination of seed from the
seedbank.
23
Kudzu
Pueraria lobata
37
35
3
3
3
35
Habit: Perennial, aggressive, semi-woody vine; forms dense mats
covering other vegetation, structures, etc.
Leaves: Alternate, compound with 3 large leaflets; may be hairy.
Stems/Bark: young stems hairy, becoming smooth, brown; up to
7.5 cm (3 in) in diameter; vines that grow upright develop bark
and annual rings, and overwinter; more robust than prostrate vines
on flat ground; may grow up to 18 m (60 ft) in one season.
Flowers: Reddish, purple, pea-like, grow on upright spikes (up to
15 cm) from leaf axils; bloom from August to September, fragrant.
Fruits/Seeds: Dark brown, dry, clustered, flat, legume seed pods,
3-8 cm long, covered with stiff golden-brown, spreading hairs,
each with up to 9 seeds.
Habitat: grows in full sun on a variety of soils; prefers deep
loams.
Reproduction: By seed, root expansion and fragmentation; roots
develop from nodes, forming root crowns every 1-2 square feet.
Similar Species: hog-peanut (Amphicarpaea bracteata) has
similar leaves, pale pink flowers in clusters - not spikes.
Comments: Fixes nitrogen.
Monitoring & Rapid Response: Monitor open disturbed areas
and forest edges; hand pull young plants, removing entire root
crown; remove all plant material from site and destroy; mowing,
grazing or tilling throughout growing season depletes root storage,
weakens plant; most effective in conjunction with herbicide; kudzu
is fire resistant; herbicides most effective in fall; older infestations
require higher herbicide concentrations; treat cut stems with
herbicide; basal bark treatment effective; foliar herbicide
application also effective.
As this species has a limited distribution in Michigan, it is
important to document new occurrences.
4
18
Please obtain flowering or fruiting specimens and submit to: Anton
Reznicek, Curator (Vascular Plants), University of Michigan
Herbarium, 3600 Varsity Drive, Ann Arbor, MI 48108-2287.
24
Oriental Bittersweet
Celastrus orbiculata
1
18
1
18
23
1
Habit: Deciduous, woody, twining vine.
Leaves: Simple, alternate, rounded, finely toothed, glossy; leaf
tips acute or acuminate; 5-13 cm long; turns yellow in fall.
Stems: Light brown, often with noticeable lenticels; solid white
pith; can climb 18 m (60 ft) high in trees and reach 10 cm (4 in) in
diameter.
Flowers: Small; greenish yellow; 5-petaled; clustered in leaf axils;
bloom in May-June.
Fruits/Seeds: Outer skin (green in summer and yellow orange in
fall) covers a red, fleshy aril, which contains 3-6 seeds; fruits
clustered in leaf axils; colorful fruit often remains on vines
through the winter.
Habitat: Native to Asia; found in grasslands, open woods,
woodland edges, undisturbed forests, roadsides and fencerows;
extremely shade-tolerant.
Reproduction: By prolific seed production and spreading
underground roots that form new stems.
Similar Species: Native - American or climbing bittersweet
(Celastrus scandens) - has elliptical rather than rounded leaves;
flowers and fruits terminal rather than axillary.
Comments: Oriental bittersweet hybridizes with American
bittersweet (C. scandens), making it a genetic threat to the native
species; may impact host species by reducing photosynthesis and
girdling trees; the native bittersweet (Celastrus scandens) is
protected under Michigan law.
Monitoring & Rapid Response:
Monitor open woods and edge habitats in late fall when most
native plants have dropped their leaves; Oriental Bittersweet can
be readily identified by its bright yellow leaves and in the case of
female plants, persistent showy fruit, which is located in leaf axils;
for existing populations, begin control efforts in highest quality
areas and remove mature plants that provide a source of seed;
hand pull or dig up seedlings and young vines; treat cut stems with
an herbicide.
25
Herbaceous
Plants
26
Dame’s Rocket
Hesperis matronalis
3
3
14
25
14
3
14
3
Habit: Showy, biennial or short-lived perennial; ranging between
0.6-1.0 m (2-3 ft) tall; first year plants over-winter as an evergreen
basal rosette.
Leaves: Simple, alternate, lanceolate or ovate-lanceolate, toothed
margins; downy, with simple hairs above, branched hairs below;
leaves become smaller as they ascend the stem.
Stems: Upright, branched, with rough spreading hairs.
Flowers: White, pink, or purple; 4-petaled; borne in terminal
clusters; bloom from mid-May through July; fragrant, clove-like
aroma in evening.
Fruits/Seeds: Seeds are rounded, dark reddish-brown, 3-4 mm
long; held in long, erect pods (siliques), up to 12 cm in length;
ripen from June through August.
Habitat: prefers moist, well-drained loams; tolerates light shade
but prefers full sun; tolerates high alkalinity; established along
roadsides, woodlands, wetlands, old fields and open areas.
Reproduction: By abundant seed production; a single plant
produces up to 20,000 seeds.
Similar Species: Phlox (Phlox divaricata) - native phlox have five
petals.
Comments: Native to Europe; introduced in wildflower mixes; in
some areas, has been present at low levels for many years but is
now spreading aggressively like its mustard family relative, garlic
mustard.
Monitoring & Rapid Response: Dame’s rocket is easiest to
identify while in bloom during June and July; hand-pull plants
while the soil is moist; remove flower and seed heads; do not
compost; foliar herbicide applications are effective in early spring
or late fall while native species are dormant; control efforts should
continue for several years until the seedbank is exhausted.
27
Garlic Mustard
Alliaria petiolata
10
2
3410
13
10
20
10
7
10
Habit: Upright, herbaceous biennial growing up to 1 m (3ft) tall.
Leaves: Simple, alternate, triangular, toothed; lower leaves kidney
shaped with palmate venation, 2-12 cm long, scalloped edges,
arranged in a basal rosette; upper leaves stalked.
Stems: Up to about 1 m (3ft); typically one flowering stem per
rosette but may be more.
Flowers: Numerous, small, white, 4-petaled; usually in clusters at
the tops of stalks, sometimes in leaf axils; bloom late April-early
June.
Fruits/Seeds: Seeds are small, dark brown/black; in long narrow
capsules (siliques); one plant can produce up to 3,000 seeds; seeds
viable within a few days of flowering and remain viable up to
seven years; two germination periods - one in mid-spring and
another in late summer.
Habitat: Found in upland and floodplain forests, savannas, along
trails, roadsides and disturbed areas; shade tolerant but also found
in full sun; spreads rapidly.
Reproduction: Prolific seeding, preferentially outcrosses but may
self; produces basal rosette the first year, flowers the second year.
Similar Species: Basal leaves resemble those of Thaspium, Zizia,
Senecio, Viola spp; fruiting structures similar to other mustards;
can be distinguished by garlic odor when crushed.
Comments: All parts smell like garlic when crushed, especially in
spring and early summer; dominates the ground layer of forests to
the exclusion of almost all other herbaceous species; lacks
mycorrhizal fungi needed by woody plants for regeneration.
Monitoring & Rapid Response: Monitor forest edges, paths and
floodplains; remove all plants before seed is produced; begin
control efforts in highest quality areas; pull seedlings; remove
upper half of root or it may resprout; tamp soil thoroughly to
minimize recolonization and germination; cut flowering stems at
ground level; flowerheads must be removed to prevent seed
development; herbicide can be used in early spring and fall, while
native plants are dormant; continue control efforts until the seed
bank is depleted.
28
Giant Hogweed
Heracleum mantegazzianum
39
16
55
17
39
55
27
17
Habit: Extremely tall (2.5-6 m, 8-20 ft) biennial or short-lived
perennial with a deep (40-65 cm, 16-26 in) tap root.
Leaves: Alternate; large (up to 1.5 m, 5 ft wide) deeply divided
and dissected leaves; hairy beneath, leaf stalk enlarged and
surrounding the stem; upper leaves gradually becoming smaller.
Stems: Thick (5-10 cm in diameter), hollow, purple-mottled; with
coarse white hairs.
Flowers: Small, white flowers clustered into large umbels at the
top of each stem; bloom June-July; typically bloom once and then
die; although some perennials have survived after flowering.
Fruits/Seeds: Seeds in flat, dry, oval pods; 8-15 mm in length;
one plant can produce up to 100,000 seeds.
Habitat: Prefers open, moderately moist, cool sites but can be
found in a range of habitats.
Reproduction: By seed or by re-sprouts from cut stumps.
Similar Native Species: Cow parsnip is smaller, has fine white
hairs under leaves; Angelica has a smooth, hairless stem.
Comments: Classified as noxious by the federal government must remove the plant if found on property.
Monitoring & Rapid Response: Monitor riparian sites and
disturbed edge habitat in partial shade; sap causes increased
photosensitivity; may cause severe burns, blistering, dermatitis and
dark scars, and even blindness; protect skin; mowing stimulates
budding from the rootstalk; plants may be dug out – remove root;
use glyphosate or triclopyr for foliar spraying as 2,4-D and
dicamba kill leaves, not rootstalks.
As this species has a limited distribution in Michigan, it is
important to document new occurrences.
Please obtain flowering or fruiting specimens and
submit to: Anton Reznicek, Curator (Vascular Plants),
University of Michigan Herbarium, 3600 Varsity Drive,
Ann Arbor, MI 48108-2287.
29
Giant Knotweed
Polygonum sachalinensis
25
59
59
59
33
25
Habit: Perennial, herbaceous shrub up to 4 m (12 ft); although it
is larger than many woody shrubs, stems die back to the ground
each year.
Leaves: Simple, alternate, large, over 30 cm (1 ft) long and 2/3 as
wide with a heart-shaped base.
Stems: Upright, round, hollow with swollen nodes; resemble
bamboo shoots.
Flowers: Sparse, greenish flowers on a slender stalk; arise from
the leaf axils and stem tips;bloom August-September.
Fruits/Seeds: Fruits are 3-winged, seeds are dark and glossy;
wind and water dispersed.
Habitat: Native to Asia, now found along roadsides, stream and
river banks, wetlands, wet depressions and woodland edges; shade
intolerant; can tolerate a wide array of soil and moisture
conditions.
Reproduction: Primarily through rhizomes or fragments; does not
reproduce significantly by seed.
Similar Species: Native - Virginia knotweed (P. virginianum) - not
shrub-like, flowers on a slender spike. Non-native - Japanese
knotweed (P. cuspidatum) is smaller in size and its leaves have a
straight base.
Comments: Hybridizes with Japanese knotweed (P. cuspidatum).
Monitoring & Rapid Response: Monitor sunny open sites along
ditches and canals; ½" fragments can sprout and form new
colonies; resprouts vigorously after cutting, mowing, tilling and
digging; mowing twice per month may deplete the root system in
two to three years; foliar herbicide application may provide
effective control, cutting or spraying early in the season and then
spraying later may be easiest as plants will still be short enough to
spray efficiently; follow up may be required for several years;
monitor up to 20' away from original population; stem injection
has been extremely effective in trials (labor intensive), using
higher concentrations than are normally used for foliar application.
30
Japanese Knotweed
Polygonum cuspidatum
21
24
13
23
25
25
21
Habit: Perennial, herbaceous shrub reaching 3 m (10 ft); although
it is larger than many woody shrubs, stems die but stalks persit
through winter; growth form is a circular colony with interior
plants dying as colony advances outward.
Leaves: Simple, alternate, broad, 8-15 cm long, 5-12 cm wide
with an abruptly pointed tip and a flat base.
Stems: Upright, round, hollow, glaucous, often mottled; swollen
nodes surrounded by a papery membrane; persistant dead stalks
look like bamboo.
Flowers: Numerous, small, green-white flowers on a slender stalk
arising from the leaf axils and near the ends of stems; blooms
August-September.
Fruits/Seeds: Fruits are 3-winged, 8-9 mm, seeds are dark and
glossy; wind and water dispersed.
Habitat: Semi-shade tolerant; found along roadsides, stream and
river banks, wetlands, wet depressions and woodland edges; can
tolerate a wide array of soil and moisture conditions.
Reproduction: Primarily through rhizomes or fragments; does not
reproduce significantly by seed; spread by flood waters
Similar Species: Virginia knotweed (P. virginianum) - not shrublike, flowers on a slender spike.
Comments: Forms dense thickets that shade out natives;
aggressive rhizomes can damage pavement; once established,
stands are extremely difficult to eradicate.
Monitoring & Rapid Response: Monitor riverbanks, stream and
pond edges, particularly downstream from known occurrences;
can be identified most readily while in bloom, in August and
September; cutting or mowing at least 3 times per season can
reduce rhizome reserves; biweekly cutting preferable; foliar
herbicide application effective; provides best control when plants
have been cut, allowed to resprout to 3’ tall and then treated; hand
pull seedlings but not larger plants as new colonies can develop
from cut stems or rhizomes; continued control efforts are required
to keep this species in check.
31
Japanese Stilt Grass
Microstegium vimineum
37
4
18
4
18
30
50
Habit: Annual grass growing up to 1 m (3 ft) tall.
Leaves: Alternate, lance-shaped, thin, 5.0-7.5 cm long; .03-1.5
cm wide, slightly hairy on both surfaces with a line of silver hairs
down the center on the upper surface; tapers at both ends, pale
green turning slightly purplish in the fall.
Stems: More or less reclining, up to 100 cm (40 in) long.
Flowers: Inflorescences multiple, terminal or arising from leaf
axils; paired flowers with one sessile and one stalked flower;
spikelets hairy.
Fruits/Seeds: Seed is a yellowish-red, oval grain ripening in
September-October; one plant can produce up to 1,000 seeds per
plant, remain viable for 3-5 years.
Habitat: Shade tolerant; does not tolerate full sun or standing
water; found in streambanks, disturbed areas, roadsides, ditches.
Reproduction: By seed and rooting nodes along the stem.
Similar Species: Whitegrass (Leersia virginica) is smaller, with
1-flowered spikelets, while those of stilt grass are paired.
Comments: This species is not yet recorded in Michigan
Monitoring & Rapid Response: Monitor shady moist sites; hand
pull, mow or burn in fall during flowering but before seed set,
timing critical; burning useful in conjunction with herbicide;
imazameth preferred herbicide as it kills stilt grass but not sedges,
ragweeds or legumes; less selective herbides and pre-emergent
herbicides are inappropriate except for highly degraded sites;
follow-up required until seedbank is exhausted.
As this species is not yet recorded in Michigan,
it is important to document new occurrences.
Please obtain flowering or fruiting specimens and
submit to: Anton Reznicek, Curator (Vascular Plants),
University of Michigan Herbarium, 3600 Varsity Drive,
Ann Arbor, MI 48108-2287.
18
32
Leafy Spurge
Euphorbia esula
25
25
23
24
32
23
5
24
Habit: Herbaceous perennial ranging in height from 15-92 cm (636 in).
Leaves: Simple, alternate, long, narrow, bluish green; usually
pointed and drooping with smooth margins; exude white milky sap
when crushed.
Stems/Roots: Upright stems that branch towards the top of the
plant; dry stems may persist into the winter and following summer;
stems also release white, milky sap when broken; deep taproot, up
to 3.5-4.5 m (12-15 ft) deep; tough, woody extensive root system
that may spread laterally up to 10 m (35 ft); large root reserves
allow plant to recover from most disturbances.
Flowers: Small, yellowish-green flowers with fused petals
forming a cuplike structure; bloom mid-June to late-July.
Fruits/Seeds: Smooth, oblong, gray-brown seeds; one plant can
produce up to 200 seeds; high germination rate; viable up to 8
years with adequate moisture.
Habitat: Roadsides, prairies, savannas, gravel pits, open areas.
Reproduction: By prolific seed production and long distance seed
dispersal (up to 4.5 m); also spreads rapidly though its persistent
root system from crown and root buds that over-winter under the
soil surface.
Similar Species: Flowering spurge (Euphorbia corollata) - has
white flowers and erect leaves; non-native Cypress spurge
(Euphorbia cyparissias) has stem leafblades less than 2.5mm
wide.
Comments: Classified as noxious in Iowa, Minnesota, and
Wisconsin.
Monitoring & Rapid Response: Monitor open sites and
woodland edges; early detection is critical; leafs out early in
spring; bright yellow-green bracts appear in late May or early
June, seedlings develop buds w/in 7-10 days of emergence; long
shoots spread laterally (up to 4.8 m deep); pulling, digging,
burning and tilling may cause increase; foliar herbicide application
provides effective control of small occurrences; surveillance and
control efforts needed for 5-10 years; biological control agents
33
undergoing research currently..
Mile-a-minute Weed
Polygonum perfoliatum
42
54
50
50
54
Habit: Herbaceous, annual, fast-growing, trailing vine; covers and
eventually kills its host vegetation; variable height.
Leaves: Simple, alternate, triangular, light green-blue, barbs on
the underside.
Stems: Reddish, narrow, covered with barbs that attach to other
plants; stems with circular, cup-shaped, leafy appendages (ocreas)
that surround the stem; stems up to 7 meters long.
Flowers: Small, unnoticeable, white, closed, emerge from ocreas
along the stem; flower in June.
Fruits/Seeds: Metallic, greenish-white, turning dark blue in fall,
pea-sized, clumped berries.
Habitat: Relatively shade intolerant; found on moist sites in open
disturbed areas, woodland edges, wetlands, stream banks.
Reproduction: Mainly through self-pollinated seed production.
Similar Species: Mile-a-minute weed’s triangular, light greenblue leaves are distinctive.
Comments: Native to East Asia, introduced in the 1930s.
Monitoring & Rapid Response: Monitor roadsides, thickets,
streambanks, meadows, woodland edges, clearcuts and utility
right-of-ways; most easily recognized in late March and early
April as it germinates early in the season; for small infestations,
hand-pulling, mowing and cultivating may provide effective
control by preventing flowering and seed production; remove and
dry vines before disposal; wear heavy gloves; foliar herbicide
application provides effective control - as the leaves have a waxy
coating, a surfactant will help the herbicide adhere.
As this species is not yet recorded in Michigan,
it is important to document new occurrences.
32
42
Please obtain flowering or fruiting specimens and
submit to: Anton Reznicek, Curator (Vascular Plants),
University of Michigan Herbarium, 3600 Varsity Drive,
Ann Arbor, MI 48108-2287.
34
Narrow-leaved Bitter-cress
Cardamine impatiens
33
33
33
33
33
33
Habit: Herbaceous annual or biennial; grows up to 2 feet in
height.
Leaves: Pinnately divided with numerous (6-20), sharply toothed
leaflets, with membranelike, narrow, pointed auricles at the leaf
base (see circled structure in photo); basal leaves are arranged in a
rosette and pinnately divided; 3-11 leaflets with rounded lobes.
Stems: Erect, glabrous
Flowers: Small, white, up to 2.5 mm (0.1 in.) long; petals lacking
or shorter than the sepals, bloom May to August.
Fruits/Seeds: Slender seedpods (siliques) on spreading-ascending
to erect pedicels, 1.5-2 cm (0.6-0.8 in.) long; 10-24 seeds; ripen
from May to September.
Habitat: Established in Michigan; found on banks, along thicket
margins, shady woods and on moist limestone rocks and cliffs.
Reproduction: Seeds project out of siliques.
Similar Species: Native - Sand bitter-cress (C. parviflora) and
Pennsylvania bitter-cress (C. pensylvanica) - the most important
distinguishing characteristic of C. impatiens is the narrow, pointed
auricles at the base of the leaves.
Comments: Easily dispersed due to its seed shooting ability; can
form dense stands outcompeting native species.
Monitoring & Rapid Response: Monitor moist forested sites in
spring and summer; can be identified by its sagittate-auriculate
leaf bases. Hand pull and remove all plants before seed dispersal.
As this species has a limited distribution in Michigan, it is
important to document new occurrences.
Please obtain flowering or fruiting specimens with
the diagnostic leaf bases and submit to: Anton
Reznicek, Curator (Vascular Plants), University of
Michigan Herbarium, 3600 Varsity Drive, Ann Arbor,
MI 48108-2287.
35
Narrow-leaved Cat-tail
Typha angustifolia
47
52
52
52
Habit: Aquatic, emergent perennial ranging from 1.2-3.7 m (4-12
ft) in height.
Leaves: Upright, flat, long (up to 1 m) and narrow (0.6-1.25 cm
wide) with parallel veins; dark green; rounded on back of the leaf.
Stems: Upright, 1-2 m long.
Flowers: Borne in dense, dark brown, terminal spikes; separated
into male and female clusters with the male flowers occurring 2.010 cm above the female flowers. Male portion 7-20 cm long and
7-15 mm wide; female portion 10-20 cm long and 1-2 cm wide.
Fruits/Seeds: Numerous, tiny seeds; one plant can produce
250,000 seeds; seeds are wind dispersed in the fall and spring;
may remain viable in the seed bank for up to 100 years.
Habitat: Native to Eurasia; found in wetlands, ditches, stream and
lake shores and wet depressions; tolerates high levels of silt,
nutrients and salt.
Reproduction: By seed establishment on bare soil and
vegetatively by thick spreading rhizomes; also by fragmentation.
Similar Native Species: Common cat-tail (Typha latifolia)- no
gap between male and female portions of flower head, wider
leaves (1.0-2.0 cm).
Comments: Typha angustifolia hybridizes with the native
common cat-tail (Typha latifolia) to produce Typha X glauca;
hybrid cat-tail larger than parents, sterile; reproduces vegetatively
through rhizomes; tolerates a greater range of conditions than
parents; cattail-dominated habitat in the Midwest has increased
dramatically over the past few decades as Typha angustifolia and
T. X glauca have increasingly colonized wetlands.
Monitoring & Rapid Response: Eliminating narrow-leaved cattail impractical but all cat-tail species may become invasive; 50%
open water preferable; aerial photos useful in assessment; where
water level manipulation is possible, cut or burn stems just before
flowering to cut off oxygen to roots and flood to at least 3’-4’;
water levels from 4’-5’ encourage muskrats; foliar herbicide also
effective, particularly when followed by cutting and flooding;
prescribed fire ineffective without herbicide or flooding.
36
Purple Loosestrife
Lythrum salicaria
32
2
2
6
33
33
25
22
3
Habit: Herbaceous, perennial, stout, erect, 0.5 to 2.0 meters in
height, densely pubescent, especially the upper part of the plant,
pubescence can be variable; strongly developed taproot which
becomes woody with plant maturity.
Leaves: Leaf shape variable, lanceolate to almost linear, opposite
or whorled; sessile to somewhat clasping; 3-10 cm with larger
leaves at the base.
Stems: Four-angled; glabrous to pubescent.
Flowers: Numerous, purple (can also be white or light pink),
terminal spike-like inflorescences in axillary clusters of two to
several; bract and floral tube pubescent; 5-7 petals about 7-11 mm
long; petioles red-purple, 7-12 mm; stamens mostly 12; blooms
July to October.
Fruits/Seeds: Capsule with small seeds; prolific seed production.
Habitat: Shade intolerant but can tolerate up to 50 percent shade;
found in marshes, bogs, shores, borders of rivers and streams,
ditches, other disturbed wet soil areas; tolerates a wide range of
soils but prefers high organic soils.
Reproduction: By seed, or vegetatively by resprouting from cut
stems and regenerating from pieces of root stock.
Similar Species: Native: winged loosestrife (Lythrum alatum) has solitary flowers borne in axils of small bracts; petals 4-7 mm
long; leaves are larger toward base of plant; fireweed (Epilobium
angustifolium) has 4-petaled flowers and leaves taper at base.
Comments: Attractive but persistent weed; spreads vigorously in
moist soil conditions; crowds out native wetland plant species.
Monitoring & Rapid Response: Monitor wetlands, lake and
stream banks, and ditches in July and August when plants are in
bloom; hand pull seedlings; remove all flower and seed heads;
foliar spraying with herbicide after peak bloom (late August)
provides effective control but may damage non-target plants; apply
herbicide with an absorbent cotton glove, worn over a chemical
resistant glove, for more selective control; a biological control, the
Galerucella beetle, provides effective control (on smaller
populations the beetle colonies may die out).
37
Reed Canarygrass
Phalaris arundinacea
25
25
23
25
27
23
6
610
Habit: Cool-season, colonial, perennial grass ranging from 0.72.4 m (2.5-8 ft) tall; forms dense monotypic stands.
Leaves: Flat leaf blades; rough in texture; 1.9-2.6 cm wide and up
to 45 cm long; top blades are horizontal with a prominent
transparent ligule.
Stems/ Roots: Stems are upright; bluish-green in color. Root
system is a thick, fibrous mat of rhizomes.
Flowers: Found in crowded, branched clusters at the end of each
stem. Flower clusters dense and spike-like at immaturity,
spreading open at maturity.
Fruits/Seeds: Small, shiny brown seeds; dispersed by water,
humans, animals and machinery.
Habitat: Native to temperate regions of North America and
Europe; most colonies found throughout the Midwest are thought
to be escapes of cultivated and European varieties; widely planted
for erosion control, now found throughout wetlands, ditches,
stream and pond banks, and wet meadows.
Reproduction: Primarily through dense, mat-forming, spreading
rhizomes; also by seed.
Similar Species: Native blue joint grass (Calamagrostis
canadensis) occurs in many of the same sites but is draping rather
than upright.
Comments: Reed canarygrass is a cool-season grass.
Monitoring & Rapid Response: Monitor moist, fertile sites and
wetlands; most visible in spring when inflorescences expand to
facilitate pollination; all control methods require ongoing
monitoring and follow-up for 5-10 years until seedbank is
exhausted; for small populations, in July or August, tying large
clumps together, cutting off stems and immediately spraying them
with herbicide is effective;root fragments may resprout; burning,
mowing, discing and plowing must be ongoing - one-time efforts
may increase population; can be effectively combined with
herbicide or flooding where possible; herbicide provides effective
control; reseeding beneficial.
38
Giant Reed
Phragmites australis
6
2
23
2
23
2
34
Habit: Stout, warm-season perennial grass ranging in height from
1.8-3.9 m (6-13 ft).
Leaves: Alternate, flat, smooth leaf blades; 25-50 cm long, 1-3.5
cm wide; hairy ligules; green to grayish-green, yellow-orange in
fall.
Stems: Stems upright, rigid and hollow; up to 2.5 cm in diameter.
Flowers: Dense branched clusters on bearded axis at the end of
each stem; becoming open and feathery at maturity.
Fruits/Seeds: Seeds with white hairs below that are almost as long
as the seed; prolific seeder but seed is not always viable.
Habitat: Native to North America and found around the world;
aggressive colonies are thought to the result of genetic crossing
between native and more invasive European varieties. Found in
marshes, wetlands, ditches, swales, stream and pond banks.
Reproduction: Primarily through an extensive, aggressive system
of horizontal and vertical rhizomes that can live for 3-6 years;
rarely by seed establishment.
Similar Species: Phragmites is distinctive and
much taller than most other grasses. The state threatened wild rice (Zizania aquatica var. aquatica) though
quite tall, lacks the feathery appearance; large nonflowering plants of reed canarygrass (Phalaris
arundinacea) appear similar but lack hairy ligules.
Comments: Forms dense, impenetrable stands.
Monitoring & Rapid Response: Monitor wetlands, ditches and
moist sites, particularly adjacent to areas which receive nutrient
rich run-off or road salt; mowing, discing and digging may
increase populations; foliar herbicide spraying in late summer
provides effective control for large dense stands; may be
combined with August mowing and herbicide application of
resprouts; for small populations, in July or August, tying large
clumps together, cutting off stems and immediately spraying them
with herbicide is effective; where controlled flooding is possible,
cutting off Phragmites shoots and flooding them 3 feet deep for at
39
least 4 months during the growing season may provide control.
Spotted Knapweed
Centaurea maculosa
26
23
6
6
12
25
25
Habit: Short-lived herbaceous biennial or perennial reaching 0.61.2 m (2-4 ft).
Leaves: All leaves pale or grayish green with rough fine hairs;
basal leaves form a rosette which may persist for up to four years;
basal and lower stem leaves up to 15 cm long; leaflets deeply
divided to irregularly lobed, tapered at both ends; upper stem
leaves smaller (2-7 cm in length) with few lobes or smooth
margins.
Stems: 1-7 upright rough stems that branch towards the upper half
of the plant.
Flowers: Numerous, pink-purple, terminal solitary flowers at the
end of each stem; phyllaries with dark tips and fringed margins;
bloom from July-September.
Fruits/Seeds: Small brown wind-dispersed seeds; germinate
throughout the growing season; remain viable for up to nine years.
Habitat: Roadsides and right-of-ways, old fields, pastures,
undisturbed dry prairies and oak and pine barrens.
Reproduction: By prolific seed production and to a lesser extent
by lateral roots.
Similar Non-Native Species: Russian knapweed (Centaurea
repens), diffuse or white-flowered knapweed (C. diffusa), black
knapweed (C.nigra), brown knapweed (C. jacea), short-fringed
knapweed (C. nigrescens), and yellow star thistle (C. solstitialis).
The best way to distinguish spotted knapweed is by the dark tips
and fringed margins of its phyllaries.
Comments: A serious threat to western rangelands; may cause
skin reactions in some individuals.
Monitoring & Rapid Response: Monitor well-drained, sunny
sites – knapweed is recognizable throughout the growing season;
wear gloves, long pants and sleeves to prevent skin contact; begin
control efforts in highest quality areas; pull or dig plants in small
infestations; remove entire root; remove flower/seed heads from
site; tamp down soil; foliar herbicide spraying of rosettes is most
effective (before stem elongation); continue control annually until
the seedbank is exhausted.
40
Swallow-worts
Vincetoxicum nigrum, V. rossicum
41
41
59
59
14
41
41
59
Habit: Herbaceous perennials; both range from 0.6-1.8 m (2-6 ft)
tall.
Leaves: Simple, opposite, narrow, oblong to ovate with a pointed
tip; dark green leaves with a smooth, waxy coating; emits a
pungent herbal smell when crushed.
Stems: Twining; may climb or creep around adjacent plants.
Flowers: Small, 5-petaled, clustered in leaf axils; bloom JuneAugust; slight rotting odor; V. nigrum: purple-black with straight
white hairs on dorsal surface; peduncles 0.3-3 cm; V. rossicum:
pale to dark maroon, purple or pink, glabrous; peduncles 2-5 mm.
Fruits/Seeds: Seed pods resemble those of milkweed; pods split
open in mid-summer to release wind-borne seeds.
Habitat: Native to southern Europe, now found in hardwood
forests, shaded woods, open prairies, fields, savannas, roadsides;
can tolerate a range of light and soil conditions.
Reproduction: By seed; vegetatively by rhizomes and shoots
from root crown of parent plant.
Similar Species: Native Apocynum spp. have similar seedpods but
are not vines.
Comments: Grows rapidly over native vegetation; wind-dispersed
seed travels long distances.
Monitoring & Rapid Response: Monitor disturbed sites and also
edges and paths in undisturbed sites; populations most visible in
late summer when the leaves turn golden and seedpods appear;
hand-pulling difficult as roots are fragile - digging preferred,
remove roots from site; prescribed fire is not effective when used
alone and may improve conditions for increased germination; may
be useful following herbicide application, to control seedlings with
less developed root systems; remove and burn seedpods; foliar
herbicide application provides effective control; cut-stem
herbicide application provids slightly less effective control; labor
intensive; multi-year monitoring and follow-up required.
Please report sightings with GPS positions to Dr. DiTommaso at:
[email protected].
41
Canada Thistle
Cirsium arvense
15
42
53
53
48
42
24
Habit: Perennial, rhizomatous thistle ranging in height from 0.61.5 m (2-5 ft); forms large monocultures.
Leaves: Simple, alternate, lance-shaped; crinkly, tapering, with
irregular lobes and spiny toothed margins.
Stems: Upright, slender and branching towards the top, becoming
increasingly hairy with age.
Flowers: Numerous, purple-lavender flowers, small flowerheads
(< 2.5 cm high), clustered at the tops of stems, blooms JuneSeptember; fragrant.
Fruits/Seeds: Seeds are small, light brown; tufts of hair attached
to the tip for wind dispersal; one plant produces between 15005000 seeds, which can germinate 8-10 days after flowering begins
and persist in the seed bank for up to 20 years.
Habitat: Found in disturbed open areas, roadsides, agricultural
fields; invades prairie and riparian areas; salt-tolerant; shade
intolerant.
Reproduction: Primarily by creeping, laterally spreading
rhizomes, but also by prolific seed production; dioecious, with
separate male and female clones; some hermaphroditic forms.
Similar Species: Native swamp thistle (Cirsium muticum) - has
pink rather than purple flowers and flower heads are sticky.
Comments: Canada thistle was introduced to North America from
Europe in the early 1600s; declared a noxious weed in Vermont in
1795.
Monitoring & Rapid Response: Monitor sunny, disturbed sites
including degraded grasslands, open woodlands, edge habitats and
restoration sites; begin control efforts in highest quality areas; pull
seedlings within 2.5 weeks after germination or they become
perennial; Canada thistle is clonal; resprouts from root fragments;
may require 5-10 years of ongoing efforts to eradicate this species;
different strains of Canada thistle respond differently to the same
herbicide; herbicides most effective with two applications per
season – spring (just before flowering) and fall (on new growth
after mowing).
42
European Swamp Thistle
Cirsium palustre
21
21
21
51
21
Habit: Herbaceous biennial ranging in height from 0.5-2 m tall.
Leaves: Thin, deeply lobed into pinnate segments, covered with
loose matted hairs and spiny teeth along margins, up to 20 cm
long; basal leaves longer than those higher in the stem in flowering
plants; leaves of basal rosettes (first year plants) are spiny, deeply
lobed, long and hairy below.
Stems: Thick, with spiny lengthwise wings along stem; sometimes
reddish; branching at the top.
Flowers: Spiny, purple flowerheads composed of disc flowers;
bloom June-August.
Fruits/Seeds: Fruit is a tiny achene, 3 mm long; attached to a
pappus or “thistledown”.
Habitat: Prefers moist, acidic soil conditions, shade intolerant;
found in ditches, wetlands, swamps, fens.
Reproduction: By wind dispersed seed.
Similar Species: The native swamp thistle (Cirsium muticum) has
non-spiny stems and flowerheads; non-native Canada thistle has
non-spiny stems and flowers.
Comments: European swamp thistle is considered a high priority
invasive species in the Hiawatha National Forest and has spread
widely throughout northern Michigan.
Monitoring & Rapid Response:
Monitor moist acidic sites including wetlands, forest edges and
fields; marsh thistle blooms in June and July but can be identified
by its thorny winged stems throughout the growing season;
mowing or cutting close to the ground throughout the growing
season can reduce infestations; flower heads should be removed
from site; foliar herbicide application effective; can be used on fall
rosettes, when plants are small (6-10") and during the bud/
flowering stage.
43
Wild Parsnip
Pastinica sativa
23
6
10
6
34
6
Habit: Tall, herbaceous perennial that dies after producing seed.
Leaves: Long (15 cm) leaves from a basal rosette on 1-2 year old
plants; mature plants with pinnately compound, alternate leaves of
5-15 oval, smooth, toothed leaflets.
Stems/ Roots: Stem is upright, unbranched, thick, hairy, grooved;
long, thick taproot.
Flowers: Numerous, small, yellow, 5-petaled, found in 5-15 cm
wide flat, terminal umbels; lateral flowers of umbel often taller
than central flowers; blooms June- mid-July.
Fruits/Seeds: Seeds are large, flat, round, yellowish; seeds can
remain viable for up to four years.
Habitat: Native to Eurasia; found in open habitats such as
prairies, savannas, and fens. Tolerates a range of soil and moisture
conditions; shade intolerant.
Reproduction: By seed
Similar Native Species: Golden alexanders (Zizia aurea)- much
shorter that wild parsnip, leaves with 3-7 leaflets. Prairie parsnip
(Polytaenia nuttallii)-leaflets oblong with few teeth, rounded
umbels.
Comments: Chemicals found in leaves, stems, and flowers of wild
parsnip can cause skin rashes, burns, and blisters, especially in the
presence of sunlight.
Monitoring & Rapid Response: Monitor grassland edges; easiest
to identify in June and July when it begins to bloom; sap causes
increased photosensitivity; may cause severe burns, blistering,
dermatitis and dark scars - protect skin; wild parsnip may be cut 1"
to 2" below the soil surface; if flowering has begun, remove flower
and seed heads; mowing, cutting throughout the season effective;
if a brush cutter or string trimmer is used, use protective clothing
and a face shield; foliar herbicide application on basal rosettes
effective; fire does not control but exposes early rosettes in spring.
44
White Sweet Clover
Melilotus alba
3
3
3
3
42
6
15
3
Habit: Herbaceous annual or biennial that can grow up to 1.5 m
(5 ft) tall.
Leaves: Compound, alternate, clover leaves with three finely
toothed leaflets.
Stems/Roots: Upright, many-branched; smooth; often hollow;
leafy stems that may be spreading near the base giving the plant a
bushy appearance. Deep taproot, extensive lateral roots.
Flowers: Numerous, white, pea-like, fragrant; crowded onto
elongated stems; bloom May-September.
Fruits/ Seeds: Fruit is a tiny, wrinkled seedpod containing 1-2
small, tough seeds; seeds may remain viable for up to thirty years;
seed germination stimulated by burning.
Habitat: Native to Eurasia; found in open, dry, disturbed sites
such as roadsides and old fields; also found in calcareous soils of
sand dunes and prairies. Shade intolerant; will tolerate nutrient
poor soils.
Reproduction: By prolific seed production; up to 350,000 seeds
per plant.
Similar Species: Non-native - Resembles yellow sweet clover
(Melilotus officinalis) which has yellow rather than white flowers;
seedlings may also resemble alfalfa (Medicago spp.) - has hairs
(pubescent) on the leaf underside.
Comments: Capable of nitrogen fixation.
Monitoring & Rapid Response: Monitor open, sunny sites;
sweet white clover is most easily identified in June and July, while
in bloom; for small infestations, pull first year plants in fall, after
the root-crown buds have developed; pull second year plans
before flowering; flowering plants should be removed and
disposed of so that seed does not develop; poorly planned
prescribed fire will increase infestations; multiple hot burns
needed, timing critical, dependent on population age structure; a
single burn may also be combined with herbicide application.
45
Yellow Sweet Clover
Melilotus officinalis
15
3
3
3
15
3
24
19
Habit: Herbaceous annual or biennial that can grow up to 1 m (3
ft) tall
Leaves: Compound, alternate, clover leaves with three finely
toothed leaflets.
Stems: Upright, many-branched; often hollow; leafy stems that
may be somewhat spreading near the base giving the plant a bushy
appearance. Deep taproot, extensive lateral roots.
Flowers: Numerous, yellow, pea-like, fragrant; crowded onto
elongated stems; bloom May-September.
Fruits/ Seeds: Fruit is a tiny, wrinkled seedpod containing 1-2
small seeds that may remain viable for up to thirty years; seed
germination stimulated by burning.
Habitat: Native to Eurasia; occurs in open, disturbed sites such as
roadsides and old fields; invades prairies, savannas and dunes;
shade intolerant; tolerates nutrient poor soils
Reproduction: By prolific seed production; up to 350,000 seeds
perplant.
Similar Species: Non-native - Resembles white sweet clover
(Melilotus alba)- which has white rather than yellow flowers;
seedlings may also resemble alfalfa (Medicago spp.), which has
hairs (pubescent) on the leaf underside.
Comments: Capable of nitrogen fixation.
Monitoring & Rapid Response: Monitor open, sunny sites;
sweet yellow clover is most easily identified in June and July,
while in bloom; for small infestations, pull first year plants in fall,
after the root-crown buds have developed; pull second year plans
before flowering; flowering plants should be removed and
disposed of so that seed does not develop; poorly planned
prescribed fire will increase infestations; multiple hot burns
needed, timing critical, dependent on population age structure; a
single burn may also be combined with herbicide application.
46
Aquatic Plants
47
Curly Pondweed
Potamogeton crispus
28
28
28
28
28
32
7
Habit: Submergent aquatic perennial; ranges from 30-80 cm (12.5 ft) in length; forms dense mats.
Leaves: Submerged, alternate, oblong, 3-9 cm long and 5-10 mm
wide; rounded at the tip; slightly clasping the stem at the base;
wavy leaf margins with fine teeth.
Stems: Compressed, 4-angled, with few branches, up to 80 cm
long and 1-2 mm wide.
Flowers: Found on dense cylindrical spikes that rise above the
water for wind pollination; bloom in late spring/early summer.
Fruits/Seeds: Small (4-6 mm long), brown, with a distinct,
pointed beak.
Habitat: Found in shallow to deep water of lakes and rivers;
pollution-tolerant; prefers alkaline, nutrient-rich waters.
Reproduction: Vegetatively by spindle-shaped turions (winter
buds that form at leaf axils and stem tips); turions lie dormant
during summer, germinate in fall; also spreads by fragmentation;
seeds probably not viable.
Similar Species: Variable leaf pondweed (Potamogeton
gramineus) but its leaf margins are not toothed.
Comments: Begins growing in early spring, dies back completely
by mid summer after blooming; inhibits growth of native plants;
midsummer die-back results in masses of dead vegetation, increase
in phosphorus levels and potential algal blooms.
Monitoring & Rapid Response: Monitor water bodies for new
colonies in spring; public education on transport mechanisms and
prevention is critical; raking/cutting at sediment surface in spring
can prevent propagule formation - remove all fragments; herbicide
applications at low rates in early spring provide effective control ,
less negative effects on native aquatic plants; - plants die back
completely by late spring or early summer so later application
ineffective; where water levels can be manipulated, fall drawdown
can kill turions.
48
Eurasian Water Milfoil
Myriophyllum spicatum
14
36
?
45
?
Habit: Submergent aquatic perennial; commonly ranges from 310 feet in length but may reach 33 ft; forms dense mats.
Leaves: Submerged, featherlike, 4-5 leaves with 9-21 threadlike
pairs of leaflets whorled around stem at each node; bright green;
limp when out of water.
Stems: Thick near the base; becoming more slender and branching
near the water surface; usually 1-3 m (3-10 ft) long.
Flowers: Inconspicuous yellow four-parted; flower spikes rise 2-4
in above water surface.
Fruits/Seeds: Fruit is a hard capsule with 4 seeds.
Habitat: Found throughout Midwestern ponds and lakes in 1-3.5
m (3-12 ft) of water, prefers disturbed shorelines and nutrient rich
waters.
Reproduction: Vegetatively by fragmentation and creeping
runners; seeds viable but not an important dispersal mechanism.
Similar Species: There are six native milfoils in Michigan; most
closely resembles northern water milfoil (Myriophyllum sibiricum)
- has 7-11 pairs of leaflets, remains rigid out of water and forms
winter buds; may also resemble coontail (Ceratophyllum
demersum) - has forked rather than featherlike leaves.
Comments: Eurasian milfoil begins to photosynthesize and grow
prolifically in early spring, allowing it to dominate an area and
limit light availability to other aquatic life, disrupting the aquatic
food web.
Monitoring & Rapid Response: Monitor water bodies for new
colonies; public education on transport mechanisms and
prevention is critical; reduce nutrient enrichment (fertilizer,
manure runoff) where possible; hand pull or rake out colonies,
removing all fragments; biological control – native herbivorous
weevil (Eurhychiopsis lecontei) shows promise; herbicides show
mixed results; check current research – treatment rapidly evolving.
49
European Frog-bit
Hydrocharis morsus-ranae
5
31
Habit: Perennial, free-floating aquatic herb that forms large
colonies, creating dense mats with tangled roots.
Leaves: Usually floating, kidney shaped with long stems, dark
purple beneath, resemble tiny water lilies, 0.5-2.25 in in diameter.
Stems: European frog-bit has strong, cord-like stolons.
Flowers: White, cup-shaped, 3-petaled with yellow dots at the
base; bloom mid-summer.
Fruits/Seeds: fruit a globose, many-seeded berry; fruit/seedset
uncommon.
Habitat: Occurs in shallow, slow-moving water on the edges of
lakes, rivers, streams, swamps, marshes and ditches.
Reproduction: primarily vegetative, through long stolons and
turions (winter buds that are produced on the stolons); in fall,
turions drop off and remain dormant until spring when they begin
to grow; one plant can produce over 100 turions a year.
Similar Species: European frog-bit superficially resembles a
water lily (Nymphaea odorata) but it is much smaller and its
flowers have only 3 petals.
Comments: Most plants are dioecious and many populations
consist of only one sex; in mixed populations, most plants are
male and little seed is produced.
Monitoring and Rapid Response: Monitor for new populations;
no control measures have been reported for this species; although
no reports are available, hand pulling or raking out colonies before
fall, when turions drop off, seems advisable.
As this species has a limited distribution in Michigan, it is
important to document new occurrences.
32
23
Please obtain flowering or fruiting specimens and
submit to: Anton Reznicek, Curator (Vascular Plants),
University of Michigan Herbarium, 3600 Varsity Drive,
Ann Arbor, MI 48108-2287.
50
Hydrilla
Hydrilla verticillata
11
18
56
11
56
Habit: Submerged, rooted, perennial; forms extensive
monocultures.
Leaves: Whorls of 3-10 thin (2-4 mm wide, 6-20 mm long), rough
leaves at the node; small spines give the leaf margin a toothed
appearance; midribs red and often spiny.
Stems: usually rooted - roots in water up to 6 m (20 ft) deep; little
branching in deep water but dense at water’s surface; forms
horizontal stems in water (stolons) and underground (rhizomes).
Flowers: Female flowers are small, white, 6-petaled, occur from
leaf axils; male flowers are green and resemble an inverted bell.
Fruits/Seeds: Cylindrical seedpods; 1-5 smooth, tiny, brown seeds.
Habitat: Found in lakes, ponds, reservoirs and ditches.
Reproduction: Vegetatively by tubers and vegetative winter buds
(turions); fragments root at nodes; seed less important.
Similar Species: Canadian waterweed (Elodea canadensis) without the toothed leaf margins, red veins, and spiny leaf midrib
of Hydrilla verticillata.
Comments: Listed federally as a noxious weed.
Monitoring & Rapid Response: Monitor aquatic habitats;
mechanical removal requires specialized machines; may need to
be repeated up to 6 times in one growing season, fragments may
produce new plants; drawdown from fall through spring may
reduce population levels; herbicides with contact poisons have
been used to control hydrilla but are non-selective and may be
highly toxic to fish; systemic herbicides reduce the overall growth
rate of this species, without eliminating it completely; biocontrols
being tested.
As this species is not yet recorded in Michigan, it is
important to document new occurrences.
Please obtain flowering or fruiting specimens and submit to: Anton
Reznicek, Curator (Vascular Plants), University of Michigan
Herbarium, 3600 Varsity Drive, Ann Arbor, MI 48108-2287.
18
1
51
Water-hyacinth
Eichhornia crassipes
42
45
45
54
32
42
32
Habit: Free floating aquatic plant ranging from 0.5-1 m in height
with distinctive air bladders that keep leaves afloat above the
water; forms dense, floating mats.
Leaves: Thick, waxy, round, broad, 10-20 cm in diameter,
cuplike, glossy, green leaves.
Stems: Spongy, erect, stems (up to 50 cm long) inflated with air
bladders towards the base.
Flowers: Showy, lavender-blue, 6-petaled flowers; upper petals
with a central, yellow, blue-bordered blotch; 8-15 flowers occur on
a single spike that can be up to 30 cm long.
Fruits/Seeds: Fruit is a 3-celled capsule with numerous tiny seeds.
Habitat: Native to the Amazon Basin, now found primarily in
southern and western wetlands, marshes, ponds, lakes, and rivers.
Reproduction: By fragmentation of stolons, adventitious root
system, and to a lesser extent by seed.
Similar Species: Pickerelweed (Pontederia cordata) has purple
flower spikes and lacks the conspicuous air bladder; not matforming.
Comments: Capable of doubling in size in two weeks. Considered
to the be one of the most troublesome aquatic weeds in the world.
Monitoring & Rapid Response: Monitor ditches, ponds,
wetlands, lakes and rivers for this species, particularly in nutrientenriched waters; most recognizable in bloom (late summer, early
fall); hand pull small populations; several herbicides are effective
– young plants move herbicides from stolons to roots faster than
old plants; old plants and flowering plants may be more
susceptible overall; herbicides are taken up more rapidly in warm
water than in cold water.
As this species is not widely distributed in Michigan, it is
important to document new occurrences.
Please obtain flowering or fruiting specimens and submit to: Anton
Reznicek, Curator (Vascular Plants), University of Michigan
Herbarium, 3600 Varsity Drive, Ann Arbor, MI 48108-2287.
52
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55
Photo Credits
1. James R. Allison, Georgia Department of Natural Resources,
www.forestryimages.org.
2. Chuck Bargeron, The University of Georgia,
www.forestryimages.org.
3. Steven J. Baskauf, PhD., Department of Biological Sciences,
Vanderbilt University Station B 351634, Nashville, TN,
www.cas.vanderbilt.edu/bioimages.
4. Ted Bodner, Southern Weed Science Society,
www.forestryimages.org.
5. Katie Bonjour, Metrobeach Metropark.
6. Nanna Borcherdt, Sitka Conservation Society,
www.forestryimages.org.
7. Ann Bove, Vermont Department of Environmental Conservation, http://aquat1.ifas.ufl.edu/photos.html.
8. Patrick Breen, Oregon State University,
www.forestryimages.org.
9. John D. Byrd, Mississippi State University,
www.forestryimages.org.
10. Suzan L. Campbell, Michigan Natural Features Inventory.
11. Raghavan Charudattan, University of Florida,
www.forestryimages.org.
12. William M. Ciesla, Forest Health Management International,
www.forestryimages.org.
13. Bill Cook, Michigan State University,
www.forestryimages.org.
14. Elizabeth J. Czarapata, http://dnr.wi.gov/invasives/photos/
index.asp.
15. Steve Dewey, Utah State University, www.forestryimages.org.
16. Donna R. Ellis, University of Connecticut,
www.forestryimages.org.
17. Terry English, USDA APHIS PPQ, www.forestryimages.org.
18. Chris Evans, The University of Georgia,
www.forestryimages.org.
19. Wendy VanDyk Evans, , www.forestryimages.org.
20. Gary Fewless, University of Wisconsin, Green Bay
21. Steve C. Garske, Great Lakes Indian Fish & Wildlife Commission, www.glifwc.org/invasives/.
22. Great Smoky Mountains National Park Resource Management
Archives, USDI National Park Service,
www.forestryimages.org.
23. Erich Haber, http://dnr.wi.gov/invasives/photos/index.asp.
24. Mary Ellen (Mel) Harte, , www.forestryimages.org.
25. Tom Heutte, USDA Forest Service, www.forestryimages.org.
26. Steve Hurst @ USDA-NRCS PLANTS Database, http://
plants.usda.gov/gallery.html.
27. Steve Antunes-Kenyon, Massachusetts Department of Agricultural Resources, http://massnrc.org/pests/index.htm.
28. Frank Koshere, Wisconsin Department of Natural Resources,
http://plants.ifas.ufl.edu/potcrifrank.html.
29. Bradley Kriekhaus, USDA Forest Service,
www.forestryimages.org.
30. Nancy Loewenstein, Auburn University,
www.forestryimages.org.
31. Todd Losee, Wetland Specialist, Wetland Assessment Program
Coordinator, Land and Water Management Division, Department of Environmental Quality.
32. Leslie J. Mehrhoff/ IPANE, www.lib.uconn.edu/webapps/
ipane/search.cfm.
33. Leslie J. Mehrhoff, University of Connecticut,
www.forestryimages.org.
34. David Mindell, Plantwise Native Landscapes.
35. James H. Miller, USDA Forest Service,
www.forestryimages.org.
36. Robert H. Mohlenbrock, USDA NRCS PLANTS Database,
www.forestryimages.org.
37. David J. Moorhead, The University of Georgia,
www.forestryimages.org.
38. Victoria Nuzzo, Natural Area Consultants,
www.forestryimages.org.
39. Pennsylvania Department of Agriculture, Massachusetts
Introduced Pests Outreach Project, http://massnrc.org/pests/
56
index.htm.
Photo Credits (continued)
40. J. Scott Peterson, USDA NRCS, www.forestryimages.org.
41. Charlotte Pyle, PhD., USDA Natural Resources Conservation
Service, http://tncweeds.ucdavis.edu/photos.html.42. Carol
Bell Randall, USDA Forest Service, www.forestryimages.org.
42. © John M. Randall/The Nature Conservancy, http://
tncweeds.ucdavis.edu/photos.html.
43. Norman E. Rees, USDA Agricultural Research Service,
www.forestryimages.org.
44. Barry Rice, sarracenia.com, www.forestryimages.org.
45. © Barry A. Rice/The Nature Conservancy, http://
tncweeds.ucdavis.edu/photos.html.
46. Cindy Roche, , www.forestryimages.org.
47. Becky Schillo, Michigan Natural Features Inventory.
48. Michael Shephard, USDA Forest Service,
www.forestryimages.org.
49. Britt Slattery, U.S. Fish and Wildlife Service,
www.forestryimages.org.
50. Jil M. Swearingen, USDI National Park Service,
www.forestryimages.org.
51. Dan Tenaglia, www.missouriplants.com, http://dnr.wi.gov/
invasives/photos/index.asp.
52. © Mandy Tu/The Nature Consercancy, http://
tncweeds.ucdavis.edu/photos.html.
53. UAF Cooperative Extension Archives, University of Alaska Fairbanks, www.forestryimages.org.
54. USDA APHIS Archives, USDA APHIS,
www.forestryimages.org.
55. USDA APHIS PPQ Archives, USDA APHIS PPQ,
www.forestryimages.org.
56. USDA ARS Archives, USDA Agricultural Research Service,
www.forestryimages.org.
57. USDA NRCS Archives, USDA NRCS,
www.forestryimages.org.
58. Linda Wilson, University of Idaho, www.forestryimages.org.
59. Wisconsin Department of Natural Resources, http://dnr.wi.gov/
invasives/photos/index.asp.
60. Gil Wojciech, Polish Forest Research Institute,
www.forestryimages.org.
61. Paul Wray, Iowa State University, www.forestryimages.org.
62. Yun Wu, USDA Forest Service, www.forestryimages.org.
57
Photo Credits
1. James R. Allison, Georgia Department of Natural Resources,
www.forestryimages.org.
2. Chuck Bargeron, The University of Georgia,
www.forestryimages.org.
3. Steven J. Baskauf, PhD., Department of Biological Sciences,
Vanderbilt University Station B 351634, Nashville, TN,
www.cas.vanderbilt.edu/bioimages.
4. Ted Bodner, Southern Weed Science Society,
www.forestryimages.org.
5. Katie Bonjour, Metrobeach Metropark.
6. Nanna Borcherdt, Sitka Conservation Society,
www.forestryimages.org.
7. Ann Bove, Vermont Department of Environmental Conservation, http://aquat1.ifas.ufl.edu/photos.html.
8. Patrick Breen, Oregon State University,
www.forestryimages.org.
9. John D. Byrd, Mississippi State University,
www.forestryimages.org.
10. Suzan L. Campbell, Michigan Natural Features Inventory.
11. Raghavan Charudattan, University of Florida,
www.forestryimages.org.
12. William M. Ciesla, Forest Health Management International,
www.forestryimages.org.
13. Bill Cook, Michigan State University,
www.forestryimages.org.
14. Elizabeth J. Czarapata, http://dnr.wi.gov/invasives/photos/
index.asp.
15. Steve Dewey, Utah State University, www.forestryimages.org.
16. Donna R. Ellis, University of Connecticut,
www.forestryimages.org.
17. Terry English, USDA APHIS PPQ, www.forestryimages.org.
18. Chris Evans, The University of Georgia,
www.forestryimages.org.
19. Wendy VanDyk Evans, , www.forestryimages.org.
20. Gary Fewless, University of Wisconsin, Green Bay
21. Steve C. Garske, Great Lakes Indian Fish & Wildlife Commission, www.glifwc.org/invasives/.
22. Great Smoky Mountains National Park Resource Management
Archives, USDI National Park Service,
www.forestryimages.org.
23. Erich Haber, http://dnr.wi.gov/invasives/photos/index.asp.
24. Mary Ellen (Mel) Harte, , www.forestryimages.org.
25. Tom Heutte, USDA Forest Service, www.forestryimages.org.
26. Steve Hurst @ USDA-NRCS PLANTS Database, http://
plants.usda.gov/gallery.html.
27. Steve Antunes-Kenyon, Massachusetts Department of Agricultural Resources, http://massnrc.org/pests/index.htm.
28. Frank Koshere, Wisconsin Department of Natural Resources,
http://plants.ifas.ufl.edu/potcrifrank.html.
29. Bradley Kriekhaus, USDA Forest Service,
www.forestryimages.org.
30. Nancy Loewenstein, Auburn University,
www.forestryimages.org.
31. Todd Losee, Wetland Specialist, Wetland Assessment Program
Coordinator, Land and Water Management Division, Department of Environmental Quality.
32. Leslie J. Mehrhoff/ IPANE, www.lib.uconn.edu/webapps/
ipane/search.cfm.
33. Leslie J. Mehrhoff, University of Connecticut,
www.forestryimages.org.
34. David Mindell, Plantwise Native Landscapes.
35. James H. Miller, USDA Forest Service,
www.forestryimages.org.
36. Robert H. Mohlenbrock, USDA NRCS PLANTS Database,
www.forestryimages.org.
37. David J. Moorhead, The University of Georgia,
www.forestryimages.org.
38. Victoria Nuzzo, Natural Area Consultants,
www.forestryimages.org.
39. Pennsylvania Department of Agriculture, Massachusetts
Introduced Pests Outreach Project, http://massnrc.org/pests/
index.htm.
58
Index
A
Acer platanoides 8
Ailanthus altissima 9
Alliaria petiolata 28
Alnus glutinosa 5
Amur Honeysuckle 13
Autumn Olive 10
B
Bell’s Honeysuckle 14
Berberis thunbergii 19
Black Alder 5
Black Jetbead 12
Black Locust 6
C
Canada Thistle 42
Cardamine impatiens 35
Celastrus orbiculata 25
Centaurea maculosa 40
Cirsium arvense 42
Cirsium palustre 43
Common Buckthorn 17
Curly Pondweed 48
D
Dame’s Rocket 27
E
Eichhornia crassipes 52
Elaeagnus angustifolia 7
Elaeagnus umbellata 10
Euphorbia esula 33
Eurasian Water Milfoil 49
European Frog-bit 50
European Swamp Thistle 43
G
Garlic Mustard 28
Giant Hogweed 29
G (continued)
Giant Knotweed 30
Giant Reed 39
Glossy buckthorn 18
H
Heracleum mantegazzianum 29
Hesperis matronalis 27
Hydrilla 51
Hydrilla verticillata 51
Hydrocharis morsus-ranae 50
J
Japanese Barberry 19
Japanese Honeysuckle 23
Japanese Knotweed 31
Japanese Stilt Grass 32
K
Kudzu 24
L
Leafy Spurge 33
Ligustrum vulgare 21
Lonicera japonica 23
Lonicera maackii 13
Lonicera morrowii 15
Lonicera tatarica 16
Lonicera x bella 14
Lythrum salicaria 37
M
Melilotus alba 45
Melilotus officinalis 46
Microstegium vimineum 32
Mile-a-minute Weed 34
Morrow’s Honeysuckle 15
Multiflora Rose 20
Myriophyllum spicatum 49
N
Narrow-leaved Bitter-cress 35
Narrow-leaved Cat-tail 36
Norway Maple 8
O
Oriental Bittersweet 25
P
Pastinica sativa 44
Phalaris arundinacea 38
Phragmites australis 39
Polygonum cuspidatum 31
Polygonum perfoliatum 34
Polygonum sachalinensis 30
Potamogeton crispus 48
Privet 21
Pueraria lobata 24
Purple Loosestrife 37
R
Reed Canarygrass 38
Rhamnus cathartica 17
Rhamnus frangula 18
Rhodotypos scandens 12
Robinia pseudo-acacia 6
Rosa multiflora 20
Russian Olive 7
S
Spotted Knapweed 40
Swallow-worts 41
T
Tartarian Honeysuckle 16
Tree of Heaven 9
Typha angustifolia 36
V
Vincetoxicum nigrum 41
W
Water-hyacinth 52
White Sweet Clover 45
Wild Parsnip 44
Y
Yellow Sweet Clover 46
59